Hobbing machine



April 11, 1939.

o. E. STAPLES ET AL 2,154,056

HOBBING MACHINE Filed March 10, 1938 3 Sheets-Sheet l INVENTOR. By 017: f. Sin/us:

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April 11, 1939- o. E. STAPLES El AL 2,154,056

HOBBING MACHINE Filed March 10, 1958 3 Sheets-Sheet 2 H aw r n :w m? WWW m Y B B N W.

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HOBBING MACHINE Filed March 10, 1938 3 Sheets-Sheet 3 INVENTOR. 414 6 027.5 t.v 5mm 6 BY fire-noon: E 6mm 1/1 ATTO Patented Apr. 11, 1939 UNITED STATES HOBBING MACHINE Otis E. Staples and Theodore F. Carlin, Cleveland, Ohio, assignors to The Cleveland Hobbing Machine Company, Cleveland, Ohio, a corporation of hio Application March 10, 1938, Serial No. 195,082

1 Claim.

The present invention relates to machinetools, especially'hobbing machines, and more particularly to the drive therefor.

An object of the present invention is the provision of novel and improved means for supporting and adjusting the worm of a worm and worm wheel drive.

Another object of the present invention is the provision of novel and improved means for supporting and adjusting the worm of a hobbing machine having a worm and worm wheel drive.

Another object of the present invention is the provision of a novel and improved hobbing machine comprising a worm and worm wheel drive and including means for sppporting and adjusting the worm thereof which will securely hold the worm in adjusted position but which can be readily manipulated to take up wear, etc.

The present invention resides in certain details of construction and combinations and arrangements of parts, and further objects and advantages thereof will be apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiment thereof, described with reference to the acoompanying drawings forming a part of this specification in which similar reference characters designate corresponding parts throughout the several views and in which- Fig. 1 is a perspective viewof a hobbing machine embodying the present invention;

Fig. 2 is a vertical section through the machine shown in Fig. 1 on the center line with portions,

in elevation with the work head lowered, the hob head rotated to a vertical position, and the hob and work arbor omitted;

Fig. 3 is a section on the line 3--3 of Fig. 2;

Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a section on the line 5-5 of Fig. 3; and

Fig. 6 is a wiring diagram of the electrical circuits of the machine.

Although the invention is susceptible of embodiment in various constructions, it is herein shown and described as embodied in a single spindle bobbing machine of general vertical construction. The bed of the'machine designated generally by the reference character A and which serves as a sump for the cutting fluid, etc., is rectangular which permits a number of machines to be ganged together, synchronized, and taken care of by a single operator. The frame of the machine designated generally by the reference character B is of hollow construction to provide maximum rigidity and minimum weight and is bolted to the bed A.

The tool head designated generally by the reference character C comprises a member l0 slidably supported on horizontal ways Ii formed integral with the frame B and located intermediate vertical ways l2 and it upon which the 5 work head, designated generally by the reference character D, hereinafter more specifically referred to, is slidably supported. A tool spindle l5, which carries the hob, isrotatably supported in a member it through the medium of antifric- 10 tion bearings, which member I6 is rotatably supported by the member lfl'coaxially with the main drive shaft ll of the machine. The tool spindle I5 is operatively connected to the drive shaft I! through the medium of mitre gears I8 and l9, 15 the former of which is provided with an elongated hub splined to the front end of the drive shaft I1 and rotatably supported in a rearwardly extending boss 20 formed integral with the member I6. The mitre gear I9 is secured to the lower 20 end of a short shaft 2| rotatably supported in the member it, upon the upper end of which is formed a spiral pinion 22 continuously in mesh with a spiral gear 23 keyed to the tool spindle IS. The hob designated generally by the reference character H is carried by a hob arbor 25 fixed at its upper end to the tool spindle l5, while the lower end thereof is rotatably supported in a bracket 26 adiustably secured to the member IS. The upper end of the tool spindle I5 is provided with a fly wheel 21 in the usual manner.

The member i6 is rotatably supported by the member l0 through the medium of a boss 28 which engages within a cylindrical aperture formed in the front wall of the member ID. Bolts 29, the heads of which engage within a circular T-slot 30, provide means for securing the member ii to the member Ill in any adjusted angular position. A vernier scale 30 on the side of the member l0 permits the hob to be quickly and accurately set to any desired angle. The tool head C may be adjusted along the ways H to move the hob toward or away from the work through the medium of a short shaft 3| rotatably supported in the frame B and provided with a worm 32 fixed thereto in any convenient manner. The worm 32 is continuously in mesh with a rack 33 secured to the underside of the member ill from which construction it will be apparent that upon rotation of the shaft 3! the tool head will be moved along the ways ll, either towards or away from the work, depending upon the direction of rotation of the shaft 3!. The forward end of the shaft 3| is made square for the reception of a wrench or the like employed in turning the same and a graduated dial 54 fixed thereto facilitates setting and adjusting the hob. The tool head C, that is the member ll thereof, is adapted tobe clamped to the ways ll inany adjusted position through the medium of bolts provided for that purpose. The member I. has a telescopic connection with a boss-like member 55 fixed to the frame B, which connection prevents the entrance of chips, etc., into the interior of the tool head while permitting the same to be readily adjusted along the ways H.

The work head designated gene by the reference character D comprises a member 55 slidably supported on the vertically spaced ways I! and I5 previously referred to formed on the frame B at the top and bottom thereof respectively. The work head, that is the frame 55 thereof, is held in engagement with the lower ways 15 by members 51 bolted to the rear side of the member 55 and projecting to the rear of the overhanging portions of the ways 15. Adjustable gibs 55 interposed between the members $51 and the ways H are provided for the purpose of taking up wear, etc., and an adjustable gib 55 interposed between a rib formed on the rear of the member 55 and the right-hand way prevents side movement of the work head D. The upper end of the work head D is maintained in engagement with the upper ways 12 50 in a manner similar to that in which the lower part of the work head is maintained in engagement with the lower ways [3 and .will not be speciflcally described.

The work is adapted to be supported between a chuck fixed to the upper end of the work spindie 45 and a tail center 4| of a tail stock 42 slidably supported on ways 45 formed integral with the work head frame or member 55. The tail stock 42 is adapted to be moved along the ways 45 and clamped in any position therealong by a manually operable lever 45 pivotally connected in the outer end of a member 45 rotatably supported in the tail stock 42. The inner end of the shaft 45 is provided with a gear, not shown. which is continuously in mesh with a rack 41 secured to the work head frame 55 adjacent the outer way 45. The lever 45 is rotatable about an axis parallel with the ways 45 to clamp and unclamp the tail stock, and about an axis normal to the ways 45 to move the tail stock therealong.

The work spindle 45 is rotatabiy supported in the work head frame by antifriction bearings and is driven from the main drive shaft 11 of the machine through a bevel gear 45 rotatably supported in a suitable aperture formed in a partition in the member 55 and splined to the shaft l1. The gear 45, or rather the hub thereof, forms a bearing for the shaft "and the teeth thereof are continuously in mesh with a bevel gear 55 fixed to the upper end of a vertically positioned spline shaft 5| the upper end of which is rotatably supported in the member 35. The lower end of the spline shaft 51 has a 'splined connection with a bevel gear 52 provided with an elongated hub through the medium of which it is rotatably supported in a rearwardly extending boss 55 formed integral with the work head frame 55. The bevel gear 52 is continuously in mesh with a bevel gear 54 fixed to the rear end of a horizontal shaft 55, the rear end of which shaft is rotatably sup ported by a suitable antifriction bearing in the rear part of the work head frame or member 35. The front end of the shaft 55 is rotatably supported in the partition 55 in the work head frame and carries a gear 51 keyed thereto which is operatively connected to a gear 55 fixed to a horizontal shaft 55 through the medium of change gears designated generally as 55 continuously in mesh with the gears 51 and 55. The change gears 55 are keyed together and are rotatably supported on a sleeve carried by a bolt which in turn is adiustably supported in a T- slot in a bracket rotatably supported coaxially with the shaft 55 and adapted to be secured in any adjusted position by suitable means, not shown. The shaft 55 is operatively connected to the work spindle 45 through the medium of a worm and worm wheel drive, the worm 52 of which is formed integral with the shaft 55 while the lvzorm wheel 55 is keyed to the work spindle According to the provisions of the present invention, means is provided for adjusting the worm 52 relative to the worm wheel 55 for the purpose of eliminating lost motion and taking up .wear therebetween. For this purpose the shaft 59 is rotatably supported in a cradle 54 which in turn is rotatably supported in a work head frame 55 for rotation about an axis offset from the axis of the shaft 55. The rear end of the cradle 54 extends into a suitable aperture formed in a work head frame 55 and the front end thereof is rotatably supported in a suitable aperture formed in the partition 55. The forward end of the cradle 54 which is enlarged, see Fig. 3, is provided with an annular flange 55 through the medium of which the cradle is adapted to be clamped in any adjustable angular position by a clamp ring 55 bolted through the medium of bolts 51 to the forward face of the partition 55. To facilitate adjustment of the cradle 54, the forward face thereof is provided with apertures 11 adapted to receive a spanner wrench. A spacer collar 15 is positioned between the gear 55 and the inside race of the antifriction hearing which supports the forward end of the shaft 55. From the foregoing description it will be readily apparent that the worm 52 may be adiusted relative to the worm wheel 55 by merely loosening the bolts 51 which hold the clamp ring, and retating the cradle 54 the required amount, after which the bolts 51 are again tightened to lock the cradle in its adjusted position.

In the embodiment shown, the work head D is moved in an upward direction to carry the work past the hob bya lead screw 55 the upper end of which is rotatably supported in the work head frame 55 while the lower end thereof engages a nut 5| rotatably supported in a bracket 52 bolted or otherwise secured to the base A in some convenient manner. Thrust bearings interposed between a shoulder on the upper end of the lead screw formed by a reduced section 55 and the work head frame 55, and the lower side of the nut 5| and the bracket 52 are provided for taking the load while permitting free rotation of both the lead screw 55 and the nut 5|. The lead screw 55 is adapted to berotated in timed relation to the rotation of the work and tool spindles to effect the feeding movement through the medium of a worm gear 55 keyed to the upper end thereof and operatively connected to a gear 55 keyed to the forward end of the shaft 55 through the medium of a worm 51 fixed to the rear end of a shaft 55 rotatably supported in the work head frame, a gear 55 fixed to the forward end of said shaft 55, and change gears designated generally as 55. The

change gears 90 are rotatably supported on a sleeve which in turn is supported on a bolt adjustably secured in a slot formed in a sector 9i. The sector 9I-is rotatably supported for annular adjustment coaxially with the shaft 88 and is adapted to be secured in any adjusted position in a conventional manner.

The main drive shaft II of the machine is operatively connected to an electric motor 93 supported on an adjustable platform located in a rece'ss in the frame B by a flexible drive connection designated generally by, the reference character 94. The rear end of the drive shaft I1 is rotatably supported in a boss 95 formed integral with the frame B and the front end thereof is rotatably supported in the member through the medium of a bevel gear 48 splined thereto. From the foregoing description it will be seen that upon rotation of the motor 90 in a predetermined direction the spindles I5 and and the lead screw 80 will be rotated in timed relation.

A rapid traverse movementis adapted to be imparted to the work head D to bring the work up to the hob and to return the work head to its starting position by a reversible motor I 00 supported on the. bed A within the frame B and operatively connected to the nut II by a worm and worm wheel drive the worm of which is keyed to the forward end of a shaft IOI rotatably supported in the bracket 82 and connected to the armature of the motor I00 by a suitable coupling I02. The worm wheel of the drive referred to is formed about the periphery of the nut 8| and is designated I03, see Fig. 2. The worm and worm wheel are of the self-locking type which prevents rotation of the nut 8I relativeto the lead screw 80 while the motor I00 is at rest, which is during the cutting operation.

The work head frame 38 is divided into two compartments by the partition 56 both of which compartments are adapted to be filled with oil to a suitable level to provide lubrication for the various parts housed therein. A telescopic guard I05 is employed over the lower ways I3 to prevent the accumulation of chips, etc., thereon. Cutting fluid is supplied to the tool by the pump I06 located in the lower part of the frame B and driven from the motor 93 through a flexible drive connection I01. The pump I06 operates only during the cutting operation since the motor 93 is operated at this time only, the pump I06, like the motor 93, being supported on an adjustable base which provides an adjustment for the drive connection.

Preferably the motors 93 and I00 are of the three-phase alternating current type. and the motor I00 is of the. reversible type. The starting and stopping of the motors is controlled by upper and lower limit switches IIO and III, respectively, of conventional construction, and a start-stop push button switch II2. also of conventional construction, the start and stop buttons H3 and H4 respectively of which are provided with ferrules adapted to limit the movement thereof. The start push button H8 is normally in the out position, that is, the position shown in the wiring diagram, but may be set in a neutral position, that is, in an intermediate position by the ferrule associated therewith, and the stop button II4, which is normally closed, may be set in open position by the ferrule associated therewith. The limit switches H0 and III are actuated and controlled by adjustable stops H5, H6 and III movably connected to 3 the upper end of the work head D. The stops -IIO and IIS engage the arms IIO and H9 of a bell crank lever connected to the operating shaft of the limit switch III to actuate the latter, and the stop III engages arms I20 and I2I of a bell crank lever fixed to the operating shaft of the lower limit switch II 0.

The motor 93 is adapted to be connected to and disconnected from the supply lines L L and 1.. through the medium of a solenoid operated circuit breaker panel I22. The operating solenoid and holding-in circuits are indicated by the reference characters e and e respectively. The motor I00 is adapted to be connected to and disconnected from the supply lines through a reversible circuit breaker panel I23, the operating solenoids and their respective holding-in circuits of which are designated by the reference characters f, f, g and a. The solenoid f closes the circuit to the motor I00 to operate the same in a direction to raise the work head D and the solenoid g is adapted to close the circuit to the motor I00 to operate the same in a direction to lower the work head. In the wiring diagram the leads to the motor 93 are designated by the reference characters T T and T and the leads to the motor I00 are designated by the reference characters T T and T. The reference character I24 designates a conventional contact relay.- The control panels I22 and I23 are preferably enclosed within the head of the frame B.

The operation of the machine is as follows:

With the machine at rest and the work head in its down position, the electrical circuits are as shown in the wiring diagram. A work blank is secured in position between the work spindle chuck and the tail center while the work head is in its up position, after which the start button H3 is pressed to close the circuit to the contact relay I24 which, in turn, closes the circult to the solenoid 1, starting the motor I 00. The motor I 00 rotates the nut 8| at a comparatively high speed to rapidly bring the work down to the .hob. When the start button H3 is released after it has been pressed by the operator to start the machine, the relay I24 is maintained closed through the holding-in circuit f which has been energized in the interim. Thereafter the relay I24 maintains its own circuit. The stop III is so positioned that it engages the upstanding arm I 20 of the limit switch H0 and moves the contact arm thereof to its lower position just prior to the engagement of the work with the hob. This movement of the contact arm of the limit switch IIO opens the circuit to the solenoid f and closes the circuit to the solenoid e, which in turn disconnects the motor I00 from the supply lines and connects the motor 93 thereto, thus stopping the motor I00 and starting the motor 93. The holding-in circuit e maintains the circuit to the motor 93 until the cutting'operation has been completed, at which time the stop II 5 engages the arm H8 and actuates the upper limit switch III, opening the circuit to the motor 93, and resetting the circuit to the solenoid y, so that the motor I 00 will be energized to impart a rapid return movement to the work head when the start button H3 is again pressed.

While the work head D is in its up position, the finished blank is removed, after which the start button H3 is again pressed, causing the motor I00 to rotate in the reverse direction and lower the work head. As the work head D moves down 'the stop II I engages the arm- I20 of the its initial or starting position. As the work head approaches its lower limit of movement, the stop H6 engages the lever ill actuating the limit switch III to return it to its starting or initial position. This opens the circuit to the motor ill and stops the upward movement of the work head. The machine is now in the position for the operating cycle to be repeated. The machine may be stopped at any time during the cycle of operation by pressins the stop button Ill. -After the stop button III has been pressed, the machine can again be started only by pressing the start button iii. The stop button Ill can be set in an open position by turning the ferrule associated therewith. In this event the machine cannot be operated until the ferrule is asain returned to release the stop button. If the start button H3 is set in a neutral position by means of the ferrule associated therewith, the motor 93 will not be energized when the motor I00 is stopped at the end of the transverse movement which brings the work up to the hob. This is advantageous in setting up the machine, etc. The direction of rotation of the hob relative to the feed is such that each tooth of the hob cuts from the outside of the blank towards the center with the heavy part of the cut occurring as the tooth enters the work.

From the foregoing description of the preferred embodiment of the invention it will be apparent that the objects of the invention heretofore enumerated have been accomplishedand that improved means has been provided for supporting the worm of a worm and worm wheel drive in a machine tool, especially a bobbing upper limit switch Ill and returns the same to machine, which means securely locks the worm in any adjusted position while permitting ready adjustment thereof. While the preferred embodiment of the invention has been illustrated and described in considerable detail, the invention is not limited to the particular construction shown which may be varied within the scope thereof, and it is the intention to cover hereby any and all variations, adaptations or uses thereof that come within the knowledge or practice of those skilled in the art to which the invention relates and within the spirit and scope of the appended claim.

Having thus described our invention, we claim:

In a bobbing machine, the combination of a frame, a tool spindle rotatably supported by said frame, a work spindle rotatably supported by said frame, means for producing relative feed movement between said spindles, a shaft, means for rotating said spindles in timed relation, said last mentioned means comprising a positive drive connecting said spindles and including a worm wheel fixed to said work spindle and a worm fixed to said shaft and in mesh with said worm wheel, a cradle member for supporting said worm, means for rotatably supporting both ends of said shaft in said cradle member, means for rotatably supporting said cradle member in said frame for adjustment about an axis eccentric to the axis of rotation of said shaft, said cradle member having a flange adjacent to one end thereof, and a clamp ring surrounding said flange and cooperating therewith to fixedly secure said cradle member in said frame.

OTIS E. STAPLES. THEODORE I CARI-IN. 

